PROTECTING WATER TABLE AQUIFERS FROM ORGANIC CONTAMINANTS IN THE VADOSE ZONE: A PRACTICAL APPLICATION FOR NOVICE MODELERS

1,2James A. Ridenour
1Hudson Mohawk Professional Geologists Association
2Northeastern Science Foundation, 15 Third Street, P.O. Box 746, Troy, NY 12181; icemakr1@yahoo.com

The assessment of vadose zone contamination typically falls within the purview of two distinct groups of people: expert modelers, who typically hold advanced degrees in hydrogeology or engineering, and; novice modelers (or non-modelers), whose modeling experience and expertise in contaminant fate and transport may not extend much beyond the “black box” stage. Since many of the controlling mechanisms involved in contaminant transport are not well understood by regulators and others without advanced training in contaminant hydrogeology, hydrogeochemistry or hydropedology, advanced methods for deriving regulatory cleanup levels (such as sophisticated analytical or numerical models) can be complicated and very difficult for many regulators, non-scientists and novice modelers to use effectively.

Consequently, regulators have turned to simpler techniques to evaluate the threats to water table aquifers posed by vadose zone contamination. The most common simplified approaches are based upon the application of equilibrium partitioning (EP) methods (Cf., NYSDEC-NYSDOH 2006; NYSDEC 1990; NYSDEC 1992; USEPA 1989; USEPA 1996). Because they are linked to groundwater regulatory limits that tend to be quite low, target soil cleanup levels estimated using EP methods are commonly very low as well. Achieving these targets can require large-scale remedial actions, potentially involving the excavation and treatment of large volumes of soil (and correspondingly large expenditures). Because EP techniques do not appropriately describe the physical system, they can produce meaningless or misleading results that might suggest remediating contaminated soil is necessary when it is not, and vice-versa. Several hypothetical examples are presented to demonstrate the meager scientific merit of EP methods.

The development of a novel technique is presented that uses EP as a springboard, incorporates fundamental elements of transport theory, and is calibrated using a verified transport model. The principal advantages of this approach over more sophisticated modeling packages include the ease with which users can achieve results comparable in accuracy to those yielded by far more demanding techniques, and the self-instructing nature of the application. Validation is demonstrated by successfully approximating peak contaminant concentrations for soil columns treated with picloram, chlorsulfuron, and atrazine, under widely variant transport regimes. Linear regression and Pearson product-moment correlation analyses show exceptionally good agreement between the predicted and measured values. A commonly used regulatory approach performs quite poorly, by comparison.

FIRST REPORT OF A CONCAVICARID INTERIOR (CRUSTACEA: THYLACOCEPHALA) FROM THE DEVONIAN OF NORTH AMERICA

1Alycia L. Stigall and 2Jonathan R. Hendricks
1Department of Geological Sciences and OHIO Center for Ecology and Evolutionary Studies, Ohio University, 316 Clippinger Laboratories, Athens, Ohio, 45701, USA; stigall@ohio.edu
2Department of Geology, University of Kansas, 1475 Jayhawk Blvd, Lawrence, Kansas, 66045, USA; jrhendri@ku.edu

The first Devonian concavicarid specimen from North America with internal structures preserved is described and referred to Concavicaris? sp. indet. Preserved morphology closely resembles contemporaneous concavicarids previously described from the Gogo Formation of western Australia (Briggs and Rolfe 1983). This new description of interior abdominal structures augments morphological data from previous collections of isolated concavicarid carapaces from contemporaneous strata in North America. This specimen was collected from the tidal to estuarine deposits of the Oneonta Formation of New York State, USA and may also represent the oldest thylacocephalan fossil recorded from brackish water deposits.

Keywords: Devonian, Thylacocephala, Concavicarida, abdomen, New York, Oneonta Formation, soft-part preservation

ENVIRONMENTAL CONSEQUENCES OF ACID MINE-DRAINAGE FROM DAVIS PYRITE MINE, ROWE, MASSACHUSETTS

1Jessica E. Bloom, 2Richard F. Yuretich, and 3Nora E. Gál
1Daniel B. Stephens & Associates, 6020 Academy Rd. NE, Albuquerque, NM 87109
2Department of Geosciences, University of Massachusetts, 611 North Pleasant St., Amherst, MA 01003
3Hungarian Geological Survey, Stefánia út 14, H-1143 Budapest, Hungary

Davis Mine in Massachusetts operated from 1882 until 1911, producing pyrite from a mineralized zone in the Ordovician Hawley Formation. This unit is in the Berkshire Mountains of western Massachusetts, and consists of gneiss, schist, and amphibolite, all metamorphosed to lower amphibolite grade. The ore body contains granular pyrite, with associated chalcopyrite, pyrrhotite, sphalerite, and galena. Since the time of the mine collapse in 1911, acidic drainage has been transporting very high concentrations of sulfate, iron, and trace metals from the exposed waste-rock piles in surface runoff and groundwater. Initial observations indicate that the generation and attenuation of the acid mine-drainage is in a state of dynamic equilibrium. Acidity, sulfate and metal concentrations increase in the mine effluent and groundwater as it traverses the waste-rock piles. Fish and megafauna are absent from the entire length of Davis Mine Brook, which extends 2 km downstream from the mine.

Data from multi-level wells define a shallow lens of contaminated groundwater with pH < 3, Fe > 100 mg/L and SO42- > 500 mg/L that moves rapidly through the waste-rock piles and shallow bedrock fractures. The spread of this contaminated zone is restricted by the flow of ambient groundwater from uncontaminated recharge areas. The mine effluent discharges into Davis Mine Brook where dilution by mixing with uncontaminated stream water decreases metal concentrations rapidly within the first 20m downstream. Trace metals are adsorbed on precipitated iron oxyhydroxides on the stream bed, although dissolved SO42-, Al3+, Fe, and Zn2+ remain elevated 500 m downstream relative to background concentrations. Additional input from direct groundwater discharge downstream may contribute to these elevated levels. Periods of snowmelt or rainfall cause dissolution of metal-sulfate salt precipitates in the soil and result in seasonally elevated dissolved metals, sulfate and acidity during spring and autumn.

BRINE DISPOSAL IN DEEP GEOLOGIC FORMATIONS OF THE CAMBRO-ORDOVICIAN (SAUK SEQUENCE) OF NEW YORK: IMPLICATIONS FOR NEW SALT-CAVERNGAS-STORAGE RESERVOIRS

1,2Mossbah M. Kolkas and 3Gerald M. Friedman
1Bard H.S. Early College, 525 East Houston Street, New York, NY 10002; mkolkas@verizon.net
2College of Staten Island of the City University of New York (CUNY), Department of Engineering Science and Physics, 2800 Victory Boulevard, Staten Island, NY 10314
3Northeastern science Foundation, Inc., 15 Third Street P.O. Box 746, Troy, NY 12181

An enormous amount of brine is generated during the leaching process in salt caverns designed for gas storage. Injection of the brine into deep-subsurface, porous, and permeable formations may be the most environmentally acceptable method of disposal. Thus, subsurface brine disposal has become an unavoidable and expensive part of salt-cavern storage development. As a result, careful investigation of possible brine disposal in deep geologic formations is, therefore, a prerequisite for salt-cavern development.

Petrographic and petrophysical analysis of rock samples from the Beekmantwon Group (Sauk Sequence) in central and western New York indicate that the lithologies of this group were deposited in a shallow marine of tidally influenced environment. The main rock components of the Beekmantwon Group are dolostone, sandstone, siltstone, and shale. Based on the variations in mineral composition, sedimentary microstructures, and fossil contents, the Beekmantwon Lithologies were divided into lithofacies as follows: 1) Coarse-grained sandstone (Potsdam Formation), 2) Bioturbated, sandy dolostone (Potsdam Formation); 3) Glauconitic, sandy dolostone (Potsdam Formation), 4) Stylolitic, sandy dolostone (Theresa Formation), 5) Stromatolitic dolostone (Theresa Formation), 6) Oolitic dolostone (Theresa Formation), 7) Laminated, silty to sandy dolostone (Theresa Formation), 8) Quartzose dolostone with anhydrite laths (Theresa Formation), and 9) Fossiliferous dolostone.

Mercury injection of the selected samples indicates that the Potsdam formation (sandstone) is characterized by higher porosity, permeability, and recovery efficiency compared to the overlying Theresa Formation (sandy dolostone and dolostone). The diagenetic modifications of the lithologies of the Theresa Formation have resulted in alternating impermeable to porous intervals. These impermeable intervals may serve as seal units to prevent lateral and vertical migration of gas and fluids from the Potsdam Sandstone and the porous zones of the Theresa Formation.

IN MEMORY OF PROFESSOR AMADEUS WILLIAM GRABAU (1870-1946) ON THE SEMICENTENNIAL OF HIS DEATH

Gerald M. Friedman
Northeastern Science Foundation, 15 Third Street, P.O. Box 746, Troy, NY 12181-0746;
gmfriedman@thesciencefoundation.com

A.W. Grabau (1870-1946), one of the world’s greatest sedimentary geologists divided his working life between the United States (1890-1920) and China (1920-1946). My early acquaintance with the publications of Grabau was through one of my fellow students Mrs. Mary Welleck Garretson (1896-1971) who had been a student of Grabau’s at Columbia University. Grabau served as Professor of Geology and Mineralogy at Rensselaer Polytechnic Institute before he joined the faculty of Columbia University. Grabau may truly be considered the Father of Modern Sedimentology.

This paper focuses on (1) Mary Garretson’s recollections of Grabau; (2) surviving correspondence in the Archives of the Geological Survey of China which include handwritten letters in German script addressed by Johannes Walther (1860 - 1937) to Grabau which reveal an intimate personal friendship; and (3) glimpses of Grabau’s personal life.

Grabau’s tomb is located in a pleasant memorial park of the campus of the new university of Beijing, where a white marble headstone with English and Chinese inscriptions adorns his grave.